The invention concerns a structural element for making a door leaf of a sectional door, which is movable along a predetermined path between a closed and an open setting, with a shell, especially a metal shell, having two edge portions that run essentially perpendicular to the predetermined path and parallel to each other and that are folded back on themselves to form a predetermined side structure, which has an outer surface that constitutes exterior surface of the door leaf facing away from the interior space to be closed off in the closed setting and an inner surface opposite to the outer surface, wherein at least one side structure of the shell has a fastening area provided for attachment of at least one hinge for connecting structural elements arranged successively in the moving direction of the door leaf.
Sectional doors with a plurality of door leaves having structural elements that can tilt relative to each other with respect to parallel arranged pivot axes are used in the form of garage doors and in the form of industrial doors for closing off passageways in garages and industrial bays. In both cases, the door leaf is usually situated in a vertical plane in the closed setting and in a horizontal plane overhead in the open setting. Guide rails running parallel to each other and situated on either side of the opening being closed are usually provided to guide the movement of the door leaf between the closed setting and the open setting, having a roughly vertical segment that is roughly straight and roughly parallel to the side edge of the door leaf in the closed setting, another usually horizontal segment that is roughly straight and roughly parallel to the side edge of the door leaf in the open setting, and an arc-shaped segment that joins the two straight segments to each other. To enable the movement of the door leaf along the arc-shaped segment, the structural elements forming the door leaf are joined together such that they can tilt relative to each other about pivot axes running perpendicular to the guide rails.
The structural elements forming the door leaf should on the one hand have sufficient stability to ensure a burglar-proof closure of a passageway or a driveway. On the other hand, these structural elements should have the lowest possible weight to facilitate the installation and operation of sectional doors. In traditional sectional door designs, such as are specified in EP-A-304 642 and EP-A-370 376, the structural elements forming the door leaf have a cold-formed metal shell, the thickness of the metal shell being 0.4 mm or less.
In simple sectional doors, a gap allowing a finger to be inserted is formed during a swivel movement of individual door leaf elements, which closes again in the course of the door leaf movement and creates a danger of finger injury. In the case of the sectional door leaves specified in the cited documents, this problem is solved in that the metal shells forming the structural elements have a side structure in the form of a projection, extending in the lengthwise direction of the structural ent and perpendicular to the predetermined path or parallel to the pivot axes along the upper edge in the closed setting, which in the course of a swivel movement can be tilted within a side structure in the form of an indentation, provided at the lower edge of an adjacent panel, avoiding the formation of a gap that can catch the finger.
Although the structural elements are given a stabilization by the side structures for protection against finger injury, the stabilization so achieved in many cases is still not enough to ensure a trouble-free operation. For this reason, in so-called single-shell structural elements, reinforcement struts extending perpendicular to the side structures are placed on the inner surfaces of the shells and joined to the side structure. For this purpose, the side structures usually have a fastening area, also serving for the placement of hinges joining together the successive structural elements. The reinforcement struts are usually riveted to this fastening area, while the reinforcement areas can also be used to stabilize the screws joining the hinge flaps to the fastening area. The fabrication of such single-shell structural elements involves a relatively high expense.
In many cases, sectional doors provide not only a burglar-proof closure of a passageway but also a thermal or acoustic separation of the enclosed spaces from the surroundings. For this purpose, the mentioned documents of the prior an propose structural elements in which a foam core is formed between an outer metal shell, forming the outer boundary surface of the door leaf, and an inner shell of the structural element, forming the inner boundary surface of the door leaf. Such structural elements are made by introducing a self-foaming material, such as polyurethane, into the outer shell and then closing the outer shell by means of the inner shell to limit the foaming process, clamping the inner shell onto the edges of the outer shell that are folded back on themselves. The self-foaming material then fills up the entire inner space of the double-shell door leaf element. Corresponding shell designs are indicated in EP-A-304 642 and EP-A-370 376.
The disclosure contents of these documents are herewith incorporated in this specification by explicit reference as regards the form of structural elements for making of sectional door leaves, especially the form of the side structures of these structural elements providing a protection against finger injury.
The making and installation of the just described double-shell structural elements also involves a high expense. To solve these installation problems, DE 10 2006 012 224 proposes a structural element design in which insulating slabs are placed on an inner surface of the shell, while one edge of the insulating slabs engages at least partly form-fitting with a side structure of the shell.
The disclosure content of DE 10 2006 012 224 is herewith incorporated in this specification by explicit reference as regards the design of the shells of single-shell structural elements for the making of sectional door leaves.
In any case, it has been found that the structural elements specified in the cited document are quickly damaged.